:root {
    --body-bg: #ffffff;
    /* 定义主要颜色变量 */
    --nav-bg: #ffffff;
    /* 定义主要颜色变量 */
}

body {
    margin: 0;
    padding: 0;
    font-family: "PingFang SC", sans-serif;
    background-color: var(--body-bg);
}

.navbar {
    display: flex;
    justify-content: center;
    align-items: center;
    position: fixed;
    top: 0;
    width: 100%;
    height: 68px;
    background: var(--nav-bg);
    box-shadow: 0px 4px 20px 0px rgba(0, 0, 0, 0.08);
    border-bottom: 1px solid rgba(0, 0, 0, 0.12);
    transition: top 0.3s;
    z-index: 1000;
    transition: transform 0.3s ease;
}

.navbar a {
    padding: 10px 8px;
    margin: 0 12px;
    color: rgba(0, 0, 0, 0.54);
    font-size: 1rem;
    font-style: normal;
    font-weight: 400;
    line-height: normal;
    text-decoration: none;
    transition: color 0.3s;
    white-space: nowrap;
}

.navbar a.active {
    color: #3D62C1;
    font-weight: 600;
}

.navbar a:hover {
    color: #444444;
}

.dropdown {
    display: none;
}

.container {
    width: 85%;
    margin: 90px auto 0;
    /* 内容区上边距 */
    display: flex;
    flex-direction: column;
    justify-content: space-around;
    font-size: 0;
    text-align: center;
}

img {
    margin: 0;
    padding: 0;
    width: 100%;
    height: auto;
}


@media only screen and (max-width: 960px) {
    .container {
        width: 100%;
        /* 在小于1280px时宽度为100% */
    }
}

@media only screen and (max-width: 400px) {
    .navbar {
        flex-direction: column;
        height: auto;
        /* 取消固定高度 */
    }

    .navbar a {
        margin: 8px 0;
        /* 调整竖向间距 */
        width: 100%;
        text-align: center;
    }

    .container {
        margin: 190px auto 0;
        /* 内容区上边距 */
    }
}